Epidemiology
The prevalence and incidence of Devic's disease has not been established, partly because the disease is underrecognized and often confused with MS. Devic's disease is more common in women than men, with women comprising over two-thirds of patients and more than 80% of those with the relapsing form of the disease.
According to the Walton Centre in England, "NMO seems to be present across the world unlike MS, which has a higher incidence in temperate climates and white races. Africans and Asians especially in Far East may have a higher risk of NMO, although the exact incidence of this disease is unknown, making specific conclusions difficult". Although many people who have Devic's disease were initially misdiagnosed with MS, 35% of African Americans are often misdiagnosed with MS when they really have NMO.
Devic's disease is more common in Asiana than Caucasians. In fact, Asian optic-spinal MS (which constitutes 30% of the cases of MS in Japan) has been suggested to be identical to Devic's disease (differences between optic-spinal and classic MS in Japanese patients). In the indigenous populations of tropical and subtropical regions, MS is rare, but when it appears, it often takes the form of optic-spinal MS.
The majority of Devic's disease patients have no affected relatives, and it is generally regarded as a nonfamilial condition.
Read more about this topic: Neuromyelitis Optica